The present invention relates to the field of fire safety devices for preventing flue fires, and particularly to such devices which are suited for use with wood stove flues or chimneys.
In recent years there has been considerable interest in the use of wood stoves as domestic heating devices. While such stoves have achieved considerable commercial success, some care must be taken in connection with their use to prevent excessive build-up of creosote and soot on the interior flue pipe surfaces. Even with periodic cleaning, in certain installations creosote and soot build-up can be quite rapid and is likely to lead to a chimney pipe fire.
Unfortunately there is often no way to detect the early stages of a chimney or flue pipe fire. As such a fire progresses, however, the heat generated within the flue may eventually lead to a fire which spreads to the adjoining structure. Accordingly, it would be highly desirable to detect flue or chimney pipe fires in their early stages, and to provide simple inexpensive methods for promptly extinguishing those fires to minimize the damage caused thereby.
Over the years, many flue pipe dampers, ventilators and clean-outs have been suggested, some of which might provide visual or manual access to the interior of a flue pipe. Fire detection and control were not objects of most of these devices nor were these devices generally suited for use with modern wood stoves which minimize the amount of room air drawn by the stove-flue assembly to thereby maximize the effective heating capacity of that assembly. Additionally, since the maintenance of a relatively higher flue pipe temperature tends to prevent creosote and other gases from condensing on the interior surfaces of the flue pipe, the introduction of excessive volumes of ambient air which (would have the effect of cooling flue gases, and thus accelerating creosote deposition) should be avoided.
For examples of the above-described prior art devices, please refer to U.S. Pat. No. 2,531,139 (Lilly et al) (Heater with Safety Screen Air Inlet), German Pat. No. 829,779 (Diermayer); U.S. Pat. No. 424,035 (Sweetland) (Hot Air Furnance); and French Pat. No. 721.861 (Dreyfus), each of which were cited in connection with my above-identified related application. See also the following patents relating to stove pipes comprising ventilating means: U.S. Pat. No. 205,985, now U.S. Pat. No. 4,325,917 (Way) (Stove Pipe Ventilator); U.S. Pat. No. 254,049, now abandoned (Robinson) (Stove Pipe); U.S. Ser. No. 673,476 (Robinson); U.S. Pat. No. 941,900, now U.S. Pat. No. 4,197,480 (Wood) (Combined Ventilator and Smoke Consumer); U.S. Pat. No. 2,072,758 (Libby) (Soot and Creosote Eliminator) and U.S. Pat. No. 2,545,148 (Jones) (Flue Pipe Section with Check Draft Damper).
Thus, a need still exists to detect and prevent flue fires in a manner which does not unduly increase their incidence.